Apparatus for the continuous casting of metal



ROSS! APPARATUS FOR THE CONTINUGUS CASTING 0F' METAL Filed May 15. 1947Aug. 8, 1950 2 Sheets-Sheet 1 lill/:(1111,

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ATTORNEY l. ROSS! APPARATUS FOR THE CONTINUOUS CASTING OF METAL FiledMay l5, 194.7

Aug., s, 195o 2 Sheets-Sheet 2 i N ENTOR.

Mm* ATTORNEY Patented Aug. 8, 1950 APPARATUS FOR THE CONTINUOUS CASTINGF METAL Irving Rosal, Morristown, N. J. Application May l5, 1947, SerialNo. 748.181

(Cl. 22-5'L2) 3 Claims.

'I'his invention relates to the continuous casting of metal,andllertalns particularly to means for conveying the molten metal from areservoir or holding furnace to the casting mold where the metal issolidified.

In certain prior art processes for the continuous casting of metal, asexemplified by Patents Nos. 1,868,099, 2,145,438 and 2,195,809 thecasting mold is secured directly to the reservoir or holding furnace,and the molten metal flows directly from the reservoir into the mold. Inother prior art processes, as exemplified by Patents Nos.

2,079,644, 2,284,703 and 2,301,027 the molten.

metal is poured from a ladle into the open upper end of the castingmold. In still other prior art processes, however, as exemplified byJunghans Patents Nos. 2,135,183 and 2,135,184 the molten metal isconveyed from the reservoir to the casting mold by means of a pipe ortube which extends from the reservoir to a point below the surface ofthe molten metal pool in the upper end of the casting mold. The latterprocedure has many advantages, but diillculty has been experienced infinding a suitable material for the conveying pipe or tube. Due to thehigh temperature of the molten metal and the chemical action on theconveying pipe or tube, such pipes or tubes have been found todeteriorate fairly rapidly, causing frequent shut downs for replacement.y

The rate of deterioration varies with the metal being cast and thematerial used for the conveying pipe or tube. 'I'hus while pipes ortubes of chrome-steel alloy have been found to give reasonably goodservice when casting brass, they are wholly unsatisfactory for castingaluminum.

-In casting aluminum, no really satisfactory solution has been found.for cast iron, which has given the best results so far, is erratic andunpredictable in performance. For example, a cast iron pipe may lastthree or four hours or three or four days.

Refractories have .been tried without success, and are objectionable dueto the fact that it has been observed that pieces tend to chip off. andwhen such pieces get into the casting, they cause serious trouble whenthe metal is subsequently worked, as in extruding it. for example.

Furthermore, the lack of a satisfactory material for such conveyingpipes or tubes has been an important factor in delaying the applicationof such continuous casting processes to the casting of steel, for theproblems encountered in casting brass and aluminum are multiplied in thecase of steel due to the higher temperatures required.

It is an object of the present invention to overcome these dimcultiesand to provide a conveying pipe or tube which will be serviceable forextended periodsrof time.

It is a further object of the invention to take advantage of theadditional external cooling area which may be provided to improve thecasting operation.

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment of the invention selected for purposes ofillustration is shown in the accompanying drawings, in which:

Figure 1 is a plan view.

Figure 2 is a section on the line 2-2 of Figure 1.

. Figure 3 is a plan view of a modified form. Figure 4 is a section onthe line 4-4 of Figure 3.

In all previous eiorts to solve this problem, it has been sought to finda material which would resist deterioration at the temperature of themolten metal being conveyed. According to the present invention. on thecontrary, I prevent the material of the conveying pipe or tube fromrising to a temperature suiilcient to cause deterioration. I do this byusingl a tube having a relatively thin wall made of metal preferably ofrelatively high heat conductivity, and cooling the outside of the tube.so that the metal of the tube always remains at relatively lowtemperature, as for example 300 F. .or less, at which temperatures thereis little or no tendency for the metal to deteriorate. Furthermore, inorder to prevent solidiilcation of the molten metal in the tube. I use atube having an interior cross sectional area which is ,relatively smallas compared with the cross sectional area of the mold, so that themolten metal flows through the tube at relatively high velocity. Underthese conditions. even though there is a large differential intemperature between the molten metal and the tube wall, the quantity ofheat absorbed through the tube is small and the drop in temperature ofthe molten metal from the point where it enters the tube to the pointwhere it is discharged into the mold is small. As a result, even thoughthe tube wall .is relatively cool. there is no tendency for molten tubei is a water jacket 4 having diametrically analisi lopposed inletpassages 5 and 5a and diametrlcally opposed .outlet passages 6 and Ca.Mounted within the jacket l and connected thereto at a point just abovethe inlet passages is a tubular baule 1 which f rees the cooling waterto follow the path indicated by the arrows. At the bottom. the ends ofthe tube l and jacket 4 are connected and the space therebetween isclosed by an annular ring I.

The baule wall is spaced rather closely to the wall of the conveyingtube to insure rapid circulation of water, and it will be noted that thedirection of now of the water is upward along the.

tube wall so that the coolest water is in contact with the bottom f thetube.

The lower end of the tube projects into the open upper end of thecasting mold 9 a distance such that the lower end is submerged in thepool of metal in the mold as illustrated in the draw- Preferably thetube I and the jacket I are made of copper as this metal is a good heatconductor and is resistant to heat shock. However, the invention is notlimited to the use of copper for other metals such as chrome-steelalloys may be used successfully. Ordinarily the tube is cylindrical inshape, i. e. having a uniform inside diameter, although, if desired itmay be tapered in a manner such that the inside diameter at the bottomof the tube is somewhat greater than at the top. While there is notendency for metal to freeze in the tube after full flow-has beenestablished, it has been observed that when starting an operation thefirst metal poured into the tube may trickle down one side of the tubewall and freeze thereon before full flow is established. With thetapered form of tube, however, such frozen metal will quickly freeitself frcm the tube wall as soon as full flow is established.

In the embodiment shown in Figures i and 2, it will be noted that theexterior walls of the water jacket, including the bottom wall 8 arecooled by the cooling water flowing through the jacket, and beingimmersed in the molten metal in the mold for a substantial distance,exert an important cooling effect on the molten metal in the mod, andparticularly on that portion of the maten metal which is near the centerof the mold and thus furtherest removed from the chilled mold wall. Fo-rexample, if we assume that the water Jacket has an outsidel diameter of2", that the conveying tube has an inside diameter of and that the waterjacket extends 2" below the surface of the molten metal, it wi.l be seenthat the exterior surfaces of the water` jacket provide a cooling areaof over l sq. in. which is suillcient to withdraw a substantial quantityof heat.

This effect may be greatly increased by increasing the diameter of thewater jacket in the manner illustrated in Figures 3 and 4. In this casethe diameter c-f the water jacket l' is greatly increased, being morethan two thirds of the inside diameter of the mold, and in order toinsure rapid circulation of the cooling water, the baille 1 is replacedby a, hollow baille chamber 'l' occupying a large portion of theintericr of the jacket, leaving relatively narrow outer and innerchannels for water circulation. Again, as in the embodiment shown inFigures 1 and 2 the direction of water iiow is upward along the tubewa'l, and it will also be noted that since thc cosling water enters theouter channel and moves downwardly and transversely to the innerchannel, the maximum cooling effect is exerted through the exteriorwalls of the jacket on the molten metal in the mold. In the embodimentillustrated the water is introduced tangentially through the inletpassage l' and is discharged through outlet passages C and Ia. l If enow assume an outside diameter of the water jacket of 8", with aconveying tube having a cooling area of over sq. in. If we now make thefurther assumption that a jacket of these dimensions is used with a moldhaving a diameter of 11", the mold wall to a distance 2" below thesurface of the molten metal will provide a cooling surface ofapproximately 69 sq. in. Thus, the area of the cooling surface providedby the submerged portion of the water jacket is greater than the area ofthe cooling surface provided by the opposed portion of the mold wall.

In the use of water Jacketed conveying tubes of the'type described, Ihave found it highly advantageous to design the apparatus in such mannerthat the above described relationship is maintained during castingoperations. That is, for best results,v the outside diameter of thewater jacket and the extent of submergence of the lower end of thejacket in molten metal is so adjusted with relation to the diameter ofthe mold that the cooling area of the submerged side and bottom walls ofthe jacket is at least equal to and preferably exceeds the cooling areaof the opposed portion of the mold wall.

When these conditions are maintained, so that a very substantial portionof the heat is withdrawn lfrom the interior of the pool of molten metalin the mold, it will be observed that this tends to equalize thetemperatures across the mold with the result that the depth of thecentral crater is reduced very substantially, with the metal freezingalmost in a horizontal plane. 'I'his has substantial advantages, notonly in the fact that it makes possible a more rapid rate of casting,but also in producing an lngot or billet of superior crystal structurewith little or no poromty in the center.

It will be understood that the invention may be variously modifiedandembodied within the scope of the subjoined claims.

I claim as my invention:

l. In an apparatus for the continuous casting of metal, in combination,a chilled mold, a metal tube for conveying molten metal from a source ofsupply to said mold, a water cooled Jacket surrounding said tubethroughout its length and maintaining the cooling water in contact withsaid tube throughout its length, the lower end of said tube and jacketextending into said mold and being submerged in the molten metaltherein.

2. In an apparatus for the continuous casting of metal. in combination,a chilled mold. a metal tube for conveying molten metal from a source ofsupply to said mold, a water cooled jacket surrounding said tubethroughout its length and maintaining the cooling water in contact withsaid tube throughout its length, the lower end 0f said tube and jacketextending into said mold and being submerged in the molten metaltherein, the exterior surfaces of the submerged portions of said waterjacket being cooled and exerting a cooling effect on the molten metal inthe mold.

3. In an apparatus for the continuous casting of metal, in combination,a chilled mold, a metal tube for conveying molten metal from a source ofsupply to said mold. a water cooled jacket sur.

rounding said tube throughout its length and REFERENCES CITEDmaintaining the cooling water in contact with said tubo throughout itslength, the lower ond or sold myx; lllilggxfferences are of record m thetube and jacket extending into said mold and being submerged in themolten metal therein, the 5 UMTED STATES PATENTS exterior surfaces ofthe submerged portions oi' Number Name Date said water jacket beingcooled and exerting a 1,996,335 Jones et ai Apr. 2, 1935 cooling effecton the molten metal in the mold, 2,154,234 Eppensteiner Apr. 11, 1939the cooling area. of said submerged exterior sur- 2,224,303 JunghansDec. 10, 1940 faces being at least equal to the cooling area of I02,290,083 Webster July 14, 19,42 the opposed portion o! the mold woll.2,357,780 Mueller Sept. 5, 1944 IRVING ROSSI. 2,380,109 Hopkins July 10,1945

